Minetest Lua Mainmenu API Reference 5.0.0
=========================================

Introduction
-------------
The main menu is defined as a formspec by Lua in builtin/mainmenu/
Description of formspec language to show your menu is in lua_api.txt

Callbacks
---------
core.buttonhandler(fields): called when a button is pressed.
^ fields = {name1 = value1, name2 = value2, ...}
core.event_handler(event)
^ event: "MenuQuit", "KeyEnter", "ExitButton" or "EditBoxEnter"

Gamedata
--------
The "gamedata" table is read when calling core.start(). It should contain:
{
    playername     = <name>,
    password       = <password>,
    address        = <IP/adress>,
    port           = <port>,
    selected_world = <index>, -- 0 for client mode
    singleplayer   = <true/false>,
}

Functions
---------
core.start()
core.close()

Filesystem:
core.get_builtin_path()
^ returns path to builtin root
core.create_dir(absolute_path) (possible in async calls)
^ absolute_path to directory to create (needs to be absolute)
^ returns true/false
core.delete_dir(absolute_path) (possible in async calls)
^ absolute_path to directory to delete (needs to be absolute)
^ returns true/false
core.copy_dir(source,destination,keep_soure) (possible in async calls)
^ source folder
^ destination folder
^ keep_source DEFAULT true --> if set to false source is deleted after copying
^ returns true/false
core.extract_zip(zipfile,destination) [unzip within path required]
^ zipfile to extract
^ destination folder to extract to
^ returns true/false
core.download_file(url,target) (possible in async calls)
^ url to download
^ target to store to
^ returns true/false
core.get_version() (possible in async calls)
^ returns current core version
core.sound_play(spec, looped) -> handle
^ spec = SimpleSoundSpec (see lua-api.txt)
^ looped = bool
core.sound_stop(handle)
core.get_video_drivers()
^ get list of video drivers supported by engine (not all modes are guaranteed to work)
^ returns list of available video drivers' settings name and 'friendly' display name
^ e.g. { {name="opengl", friendly_name="OpenGL"}, {name="software", friendly_name="Software Renderer"} }
^ first element of returned list is guaranteed to be the NULL driver
core.get_mapgen_names([include_hidden=false]) -> table of map generator algorithms
    registered in the core (possible in async calls)

Formspec:
core.update_formspec(formspec)
core.get_table_index(tablename) -> index
^ can also handle textlists
core.formspec_escape(string) -> string
^ escapes characters [ ] \ , ; that can not be used in formspecs
core.explode_table_event(string) -> table
^ returns e.g. {type="CHG", row=1, column=2}
^ type: "INV" (no row selected), "CHG" (selected) or "DCL" (double-click)
core.explode_textlist_event(string) -> table
^ returns e.g. {type="CHG", index=1}
^ type: "INV" (no row selected), "CHG" (selected) or "DCL" (double-click)

GUI:
core.set_background(type, texturepath,[tile],[minsize])
^ type: "background", "overlay", "header" or "footer"
^ tile: tile the image instead of scaling (background only)
^ minsize: minimum tile size, images are scaled to at least this size prior
^   doing tiling (background only)
core.set_clouds(<true/false>)
core.set_topleft_text(text)
core.show_keys_menu()
core.file_open_dialog(formname,caption)
^ shows a file open dialog
^ formname is base name of dialog response returned in fields
^     -if dialog was accepted "_accepted"
^^       will be added to fieldname containing the path
^     -if dialog was canceled "_cancelled"
^        will be added to fieldname value is set to formname itself
^ returns nil or selected file/folder
core.get_screen_info()
^ returns {
    density         = <screen density 0.75,1.0,2.0,3.0 ... (dpi)>,
    display_width   = <width of display>,
    display_height  = <height of display>,
    window_width    = <current window width>,
    window_height   = <current window height>
    }

### Content and Packages

Content - an installed mod, modpack, game, or texture pack (txt)
Package - content which is downloadable from the content db, may or may not be installed.

* core.get_modpath() (possible in async calls)
    * returns path to global modpath
* core.get_clientmodpath() (possible in async calls)
    * returns path to global client-side modpath
* core.get_gamepath() (possible in async calls)
    * returns path to global gamepath
* core.get_texturepath() (possible in async calls)
    * returns path to default textures
* core.get_game(index)
    * returns:

        {
            id               = <id>,
            path             = <full path to game>,
            gamemods_path    = <path>,
            name             = <name of game>,
            menuicon_path    = <full path to menuicon>,
            author           = "author",
            DEPRECATED:
            addon_mods_paths = {[1] = <path>,},
        }

* core.get_games() -> table of all games in upper format (possible in async calls)
* core.get_content_info(path)
    * returns

        {
            name             = "name of content",
            type             = "mod" or "modpack" or "game" or "txp",
            description      = "description",
            author           = "author",
            path             = "path/to/content",
            depends          = {"mod", "names"}, -- mods only
            optional_depends = {"mod", "names"}, -- mods only
        }


Favorites:
- core.get_favorites(location) -> list of favorites (possible in async calls)
  - `location`: "local" or "online"
  - returns {
    [1] = {
    clients       = <number of clients/nil>,
    clients_max   = <maximum number of clients/nil>,
    version       = <server version/nil>,
    password      = <true/nil>,
    creative      = <true/nil>,
    damage        = <true/nil>,
    pvp           = <true/nil>,
    description   = <server description/nil>,
    name          = <server name/nil>,
    address       = <address of server/nil>,
    port          = <port>
    },
}

- core.add_favorite(server)
  - Adds a server to the local favorites list
  - `server`: {
        `name` (server name)
        `address`
        `port`
        `description`
    }

- core.delete_favorite(idx)
  - Removes a server from the local favorites list. Returns `true` on success.
  - `idx`: Index of server to be removed

Logging:
core.debug(line) (possible in async calls)
^ Always printed to stderr and logfile (print() is redirected here)
core.log(line) (possible in async calls)
core.log(loglevel, line) (possible in async calls)
^ loglevel one of "error", "action", "info", "verbose"

Settings:
core.settings:set(name, value)
core.settings:get(name) -> string or nil (possible in async calls)
core.settings:set_bool(name, value)
core.settings:get_bool(name) -> bool or nil (possible in async calls)
core.settings:save() -> nil, save all settings to config file

For a complete list of methods of the Settings object see
[lua_api.txt](https://github.com/minetest/minetest/blob/master/doc/lua_api.txt)

Worlds:
core.get_worlds() -> list of worlds (possible in async calls)
^ returns {
    [1] = {
    path   = <full path to world>,
    name   = <name of world>,
    gameid = <gameid of world>,
    },
}
core.create_world(worldname, gameid)
core.delete_world(index)

Helpers:
core.get_us_time()
^ returns time with microsecond precision
core.gettext(string) -> string
^ look up the translation of a string in the gettext message catalog
fgettext_ne(string, ...)
^ call core.gettext(string), replace "$1"..."$9" with the given
^ extra arguments and return the result
fgettext(string, ...) -> string
^ same as fgettext_ne(), but calls core.formspec_escape before returning result
core.parse_json(string[, nullvalue]) -> something (possible in async calls)
^ see core.parse_json (lua_api.txt)
dump(obj, dumped={})
^ Return object serialized as a string
string:split(separator)
^ eg. string:split("a,b", ",") == {"a","b"}
string:trim()
^ eg. string.trim("\n \t\tfoo bar\t ") == "foo bar"
core.is_yes(arg) (possible in async calls)
^ returns whether arg can be interpreted as yes
minetest.encode_base64(string) (possible in async calls)
^ Encodes a string in base64.
minetest.decode_base64(string) (possible in async calls)
^ Decodes a string encoded in base64.

Version compat:
core.get_min_supp_proto()
^ returns the minimum supported network protocol version
core.get_max_supp_proto()
^ returns the maximum supported network protocol version

Async:
core.handle_async(async_job,parameters,finished)
^ execute a function asynchronously
^ async_job is a function receiving one parameter and returning one parameter
^ parameters parameter table passed to async_job
^ finished function to be called once async_job has finished
^    the result of async_job is passed to this function

Limitations of Async operations
 -No access to global lua variables, don't even try
 -Limited set of available functions
    e.g. No access to functions modifying menu like core.start,core.close,
    core.file_open_dialog
